Even if Windows 10 Mobile succeeded, Microsoft would still be pursuing a post-smartphone strategy

I recently wrote that Windows 10 Mobile has devolved into a "beta platform" where Microsoft is continuing investment only to maintain development of ARM and cellular connectivity in preparation for future devices.
This is not some arbitrary claim pulled from thin air. Windows Chief Terry Myerson said as much when Microsoft watcher Mary Jo Foley asked him why Microsoft continues releasing builds for the platform when it had just one percent market share.
Terry replied:

Technically, there are...two things...unique about Windows Mobile. One is cellular connectivity and the other....ARM processors…both…have a role in the technical landscape of the future.
So we're going to continue to invest in ARM and cellular. And while I'm not saying what type of device...we'll see...Windows devices, that use ARM chips...that have cellular connectivity. When you stop investing in these things, it's super hard to restart.
When you're investing into growth, it's easier, but when you're investing for technical strategy...sometimes people can question it...especially among your readers.